<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>判断一个数是否为素数</title>
</head>
<body>
    <script>
        function isZhiShu(n){
        var isZS = true;
        for( var i = 2; i<= Math.sqrt(n);i++){
            if(n % i == 0) {
                isZS = false;
            }
        }
        return isZS;
        } 
        document.write('9:'+isZhiShu(9));
        document.write('7:'+isZhiShu(7));
    </script>
</body>
</html>